On the isotropic Raman spectra of isotopic binary mixtures

Abstract

A theory is developed for the isotropic Raman spectrum of nondegenerate modes in polyatomic binary mixtures. Particular emphasis is attached to isotopic binary mixtures and the problem of dipolar resonant transfer. The thermodynamic state dependences of spectral features are investigated in some detail. Attention is focused on quantities which are experimentally accessible by isotopic dilution experiments, in particular the frequency shift of the spectrum consequent upon isotopic dilution, and also the resultant changes in spectral second moments. The theory is compared with some existing experiments on specific systems, and a number of predictions are made which are capable of being tested experimentally.